Facebook CEO Mark Zuckerberg has been learning Chinese on his own for several years (his wife, Priscilla Chan, is Chinese-American and speaks both Mandarin and Cantonese; she was his inspiration for learning). Even though his Chinese is not perfect by any means, he has learned enough to give a 30-minute Q&A in Mandarin at Tsinghua University in Beijing! It's tough to stand up in front of hundreds of people and talk... let alone speaking in a language that's not one's native tongue.